Typical green pigments which have been known include polyhalogenated copper phthalocyanine. The polyhalogenated copper phthalocyanine has excellent fastness, but it has recently been concerned about safety and environmental load because it contains a large amount of halogen atoms such as chlorine, bromine, or the like in its molecule. In addition, since the polyhalogenated phthalocyanine contains a large amount of halogen atoms and thus has a high molecular weight and the problem of decreasing coloring strength. Therefore, a pigment capable of green coloring with a compound not containing halogen atoms is required.
As a method for coloring in green with a compound not containing halogen (hereinafter, referred to as “halogen free”), a method of toning to green by mixing copper phthalocyanine as a blue pigment with a yellow organic pigment has been proposed (refer to, for example, Patent Literatures 1 and 2). However, this method has the problem of causing flooding due to mixing of two types of pigments having completely different chemical structures and the problem of causing large hue change due to sunlight exposure because light resistance varies with the types of the pigments mixed.
On the other hand, as a halogen-free compound having a green hue alone, for example, Patent Literature 3 reports a phthalocyanine compound having an imidazolone ring introduced therein, and Patent Literature 4 reports a phthalocyanine compound having a pyrido skeleton introduced therein. The phthalocyanine compound described in Patent Literature 3 assumes a green hue and thus has the property of having no need for toning and the resistance to organic solvents and acids. However, the compound has the problem of low chroma.